I help startups and businesses worldwide ship reliable, scalable software and modernize legacy systems — from architecture decisions to production deployment.

I don't just write code — I think about performance, cost efficiency, and long-term maintainability. Whether it's a mobile app, a REST API, or a complex backend system, I focus on solutions that actually work in production: optimized queries, caching strategies, global deployments, and clean architecture.

🎯 What I bring to the table: → 🛠️ Custom software tailored to real business needs → ⚙️ Process automation that eliminates operational bottlenecks → 🔄 Legacy system refactoring — modernizing old codebases without breaking what works → ⚡ Production-grade mindset: performance, observability, and cost-aware infra → 💬 Clear communication and technical leadership from architecture to delivery

• Performance optimization — profiling, query tuning, and response time reduction
• Cost-aware architecture — right-sizing infra and reducing cloud spend without sacrificing reliability
• Global deployments — CDN strategies, multi-region setups, and edge functions
• Caching strategies — Redis, HTTP caching, and database query caching
• Efficient code — avoiding over-engineering, keeping complexity low and maintainability high
• Observability — logs, metrics, and alerting so issues surface before users notice
• Process automation — internal and operational workflows
• Bottleneck identification and translation into code
• Legacy system refactoring — modernizing old codebases without breaking what works
• SaaS, PaaS, ERP, and CRM platform development
• API integrations and payment systems (Cielo, Stripe, MercadoPago)
• DevOps & scalable infrastructure with AWS, GCP, CI/CD, Docker

Building systems that boost business efficiency using best practices in architecture and code quality:

• 🧪 TDD (Test-Driven Development) for reliability and coverage
• 🧩 DDD (Domain-Driven Design) to reflect real business logic
• 🏗️ SOLID & Clean Architecture applied to critical systems
• 🧠 Robust and scalable data modeling
• 🗂️ Technical planning and development leadership
• 🛠️ Solid, secure, and high-performance back-end
• 🎨 Front-end crafted for the best user experience (UX)

Back-end: Node.js · Bun · NestJS · FastAPI · Laravel · Python
Front-end: React · Next.js · Svelte & SvelteKit · Vue · Tailwind CSS
Mobile: React Native / Lynx
Databases: PostgreSQL · MySQL · MongoDB (Prisma / Drizzle / SQLAlchemy ORM)
DevOps: AWS · GCP · Docker · GitHub Actions · CI/CD
Unit Testing: Jest · Vitest · Pytest
E2E Testing: Playwright

• Executable automation solutions using Python
• Software development for startups and companies of various sizes
• Technical leadership from architecture to delivery
• Legacy system refactoring and modernization
• Custom ERP, CRM, SaaS, and PaaS systems for real business needs

• Payment gateways (Cielo, Stripe, MercadoPago)
• External APIs and legacy systems
• Custom bots and scripts for workflow automation

🎯 Strategic planning and task organization
🗂️ Scalable architecture with a long-term maintenance focus
💬 Clear communication and stakeholder alignment
🚀 Turning ideas into real, working products

• 🌐 Website: patrickleandrodev.vercel.app
• 💼 LinkedIn: linkedin.com/in/patrick-leandro-de-sa
• 📧 Email: patrickleandrodesa@gmail.com

⭐ Ready to turn your ideas into impactful products? I'll help you build real solutions — well-planned and developed with technical excellence. Let's talk! =)